Exhaust reactor

ABSTRACT

An exhaust converter for an internal combustion engine comprising an outer housing rigidly connected directly to the exhaust outlets of the engine and a light-weight flexibly constructed inner housing suspended inside the rigid outer housing. The inner housing contains a flexibly suspended catalyst container dividing it into an inlet plenum and a thermal noncatalytic reactor compartment. Air injection means are provided in the thermal reactor. The catalytic stage reduces NOx and the thermal reactor oxidizes hydrocarbon and carbon monoxide. The light flexible construction of the inner housing allows it to expand and contract in response to thermal shock without destroying itself.

United States Patent [1 1 Marsee et al.

[4 1 Sept. 2, 1975 EXHAUST REACTOR [75] Inventors: Frederick J. Marsee,Clawson;

Robert M. Olree, Madison Heights, both of Mich.

[52] US. Cl. 23/277 C; 23/288 F; 60/306; 60/322 [51] Int. Cl. B01J8/02;F01N 3/10;FO1N 3/15 [58] Field of Search 23/277 C, 288 F; 55/DlG.30; 60/282, 301, 302, 322, 323, 304

[56] References Cited UNITED STATES PATENTS 2,834,657 5/1958 Houdry23/288 F 3,024,593 3/1962 Houdry 23/288 F 3,168,806 2/1965 Calvert.....23/288 F X 3,211,534 10/1965 Ridgway... 23/288 F X 3,307,920 3/1967Barnes 23/288 F 3,503,714 3/1970 Lang 23/277 C 3,635,031 1/1972 Haddad60/323 3,637,344 1/1971 Thompson 423/239 X 3,653,205 4/1972 Tadokoro60/322 3,669,630 6/1972 Filatov et a1. 23/288 F 3,695,851 10/1972 Perga23/288 F 3,703,083 11/1972 Tadokoro 3,751,920 8/1973 Rosenlund 3,771,96911/1973 Scheitlin 23/288 F Primary ExaminerJoseph Scovronek AssistantExaminerMichael S. Marcus Attorney, Agent, or Firm-Donald L. Johnson;Robert A. Linn; Joseph D. Odenweller 57 ABSTRACT An exhaust converterfor an internal combustion engine comprising an outer housing rigidlyconnected directly to the exhaust outlets of the engine and alight-weight flexibly constructed inner housing suspended inside therigid outer housing. The inner housing contains a flexibly suspendedcatalyst container dividing it into an inlet plenum and a thermalnoncatalytic reactor compartment. Air injection means are provided inthe thermal reactor. The catalytic stage reduces NO, and the thermalreactor oxidizes hydrocarbon and carbon monoxide. The light flexibleconstruction of the inner housing allows it to expand and contract inresponse to thermal shock without destroying itself.

18 Claims, 5 Drawing Figures PATENTEDSEP 2:975 3.902853 sum 1 0F 2 AIR-FIGURE FIGURE 2 PATENTEU EP 2 975 3, 9 02 8 5 3 SHEET 2 [IF 2 FIGURE 3FIGURE 4 FIGURE 5 EXHAUST REACTOR BACKGROUND Exhaust gas from internalcombustion engines contains components which contribute to airpollution. Components most frequently referred to are nitrogen oxides,hydrocarbons and carbon monoxide. Hydrocarbons and carbon monoxide canbe lowered by such means as running the engine at higher air/fuel ratios(e.g., above or by catalytic or thermal (i.e., noncatalytic) oxidationof these components in the exhaust system. Catalytic converters aredescribed in US. Pat. Nos. 3,166,895 and 3,154,389. Placement of thecatalyst in the exhaust manifold is described in US. Pat. No. 3,644,098.Non-catalytic converters are described in US. Pat. Nos. 3,247,666 and3,633,368.

Nitrogen oxide emissions can be lowered by such means as exhaust gasrecycle or by catalytic reduction of the nitrogen oxides. Attempts havebeen'made to lower all three (i.e., nitrogen oxides, hydrocarbons andcarbon monoxide) by catalytically reducing the nitrogen oxides in theexhaust by operating the engine rich and contacting the reducing exhaustwith a catalyst and then injecting air into the exhaust and eithercatalytically or non-catalytically oxidizing the hydrocarbon and carbonmonoxide constituents. Morris, US. Pat. NO. 3,581,490, describes such amethod in which the exhaust is first conducted to a remote catalyticunit wherein the nitrogen oxide is reduced and then to a separateflame-type oxidation unit equipped with air and fuel injectors and aspark plug igniter. Tourtellotte, US. Pat. No. 3,699,683, describes arelated system.

A major problem with previous exhaust converters is their tendency tobuckle and crack when exposed to the severe thermal shock of typicalautomobile use. In order to be effective, the units must be able to heatup rapidly. Generally, the units heat to about 1200F. in a matter of 2-3minutes. During rapid acceleration, and in the case of engine misfire,abrupt temperature excursions in excess of 1800F. can be expected. Thevarious parts of most units are rigidly connected and when they expandand contract due to temperature change they tend to buckle and crack,leading to self-destruction.

SUMMARY OF THE INVENTION According to the present invention, an exhaustconverter is provided which, due to its flexible construction, canendure thermal expansion and contraction and still maintain itsintegrity. The converter construction may be adapted to form a catalyticreactor, a noncatalytic (i.e., thermal) reactor, or a combination of acatalytic and non-catalytic reactor. In general, the structure comprisesa converter housing constructed of parts which fit together by flangesslidably fit in channels such that the individual parts canindependently expand and contract without distorting or cracking otherconnected parts.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-section takengenerally at BB of the converter including both a catalytic stage and athermal stage.

FIG. 2 is a transverse cross-section taken generally at FIG. 3 is a planview of the top baffle in the thermal stage.

FIG. 4 is a plan view of the second baffle in the thermal stage.

FIG. 5 shows an engine with the converter mounted directly to theexhaust outlets.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 5, exhaustconverter 1 connects directly to the exhaust ports of engine 2 such thatit receives exhaust gas, lowers the content of nitrogen oxide,hydrocarbon and carbon monoxide and, finally, exhausts the treated gasthrough pipe 3.

Construction of the converter is shown in detail in FIGS. 1 and 2. Itcomprises an elongated outer converter housing indicated generally by 5constructed of an upper casing 6 and a lower casing 7. Outer housing 5is made of cast metal such as cast iron. Casings 6 and 7 are open on oneside and the open sides joined by bolts 8 and 9. Internal T-shapedrecesses 10 and 11 are provided along their longitudial line of joinder.Upper casing 6 has an exhaust inlet 12 adapted by flange 13 to rigidlyconnect directly to the exhaust outlet of engine 2. Lower casing 7 hasan exhaust outlet 14 adapted by flange 15 to connect to exhaust pipe 3.

Longitudinal passage 34 is provided in upper casing 6 which is connectedby lateral spurs 19 to air injection inlets in engine 2.

Inner converter housing, indicated generally by 16, is flexiblysuspended inside outer housing 5. It is made of sheet metalconstruction, preferably sheet stainless steel. It is formed byelongated upper shell 17 and lower shell 18, both of which are open onone side and join along the edges of their open side to form innerhousing 16. The manner in which they are joined is an important featureof this invention since it provides a flexible connection which allowsthe upper and lower shells to expand and contract individually accordingto their temperature without placing undue strain on the rest of thehousing.

Both upper shell 17 and lower shell 18 have longitudinal outwardlyextending flanges 20, 21, 22 and 23 along the longitudinal edges oftheir open sides. These flanges are slidably fit into recesses 10 and11. The width of recesses 10 and His such that it allows the members fittherein to move in response to thermal expansion and contraction, but issnug enough that very little exhaust gas can escape inner converterhousing 16 between flanges 20 and 22 and flanges 21 and 23. This resultsin a flexible suspension of inner converter housing 16 inside outerconverter housing 5. Outer housihg 5 acts as a cradle to hold theflexible inner structure. The outer edges of flanges 20, 21, 22 and 23are crimped to prevent them from slipping out of recesses 10 and 11.

The edges of the ends of lower open-sided shell 18 are bent in agoose-neck form to provide upward opening channel members and 81. Theedges of the ends of upper open-sided shell 17 have extensions 82 and 83which slidably fit into channels 80 and 81, thus sealing inner housing16.

Anchor pins and 91 are inserted in openings in upper casing 6 and extendpart-way through the flange of lower casing 7. Pins 90 and 91 arelongitudinally centrally located and pass through openings in flanges20, 21, 22 and 23 and in catalyst container retainers 37 and 38 andserve to anchor these elements to outer converter housing 5 at a centrallocation. This insures that inner housing 16 will expand and contractuniformly in both directions inside outer housing 5.

An important feature of this construction is that inner housing 16 hasvery little contact with outer housing 5 and thus heat conduction isminimized. This allows inner housing 16 to heat up rapidly because ofits low mass and resultant low heat capacity while outer housing 5remains relatively cool. This feature is improved by providinginsulation 24 such as asbestos wool in the space between inner housing16 and outer housing 5.

Positioned within upper shell 17 of inner housing 5 is catalystcontainer 25 formed by side walls 26 and 27, end walls 28 and 29,perforate inlet wall 30 and perforate outlet wall 31. Screen catalystretainers 32 and 33 are positioned adjacent the perforate walls toprevent the escape of catalyst. Catalyst container 25 is loosely fit inupper shell 17 such that when it extends and contracts it does notdistort inner housing 16. Even if container 25 presses against the sidewalls of upper shell 17, it can be seen that these walls are supportedby flanges 20 and 21, which can flex in recesses and 11 to accommodatesuch pressure without breaking.

Attached longitudinally along both side edges of perforate outlet wall31 are channel members 35 and 36. Catalyst container support members 37and 38 are slidably fit into channels 35 and 36 and in-between flangesand 22 and flanges 21 and 23. This flexible suspension permits catalystcontainer to independently expand and contract within inner housing 16without distorting it or causing it to rupture.

Attached transversely at both ends of catalyst container 25 are channelmembers 84 and 85. Angle members 86 and 87 are slidably fit one intochannels 80 and 84 and the other into channels 81 and 85 thussubstantially sealing inlet plenum 40 from outlet plenum 41 except forthe flow path through perforate inlet wall and perforate outlet wall 31of catalyst container 25.

Catalyst container 25 divides inner housing 16 into inlet plenum 40 andoutlet plenum 41. The embodiment shown in FIGS. 1 and 2 includes both acatalytic reactor section and a thermal reactor section. In thisarrangement, outlet plenum 41 functions as the thermal non-catalyticreactor in a manner which will be explained later.

Inlets 42 of inlet plenum 40 are fitted with tubular slotted baffles 43which are flexibly retained in inlets 42 by flanges 44 and 45. Inlettube 50 extends inside exhaust inlet 12 and has embossed end 51 slip fitinto tubular baffle 43. When outer housing 5 is rigidly connected toengine 2, flexible tube 50 engages exhaust port-liner 52, forming anexhaust flow path from the exhaust port directly into inlet plenum 40.The flexibility of tube 50 is another important feature of the inventionbecause the engine remains much cooler than the inner converter housingand thus the engine and inner housing expand at much different rates.Flexible tube 50 allows each element to expand and contract at its ownrate without placing strain upon the other element which could lead torupture.

Air injection conduits 55 and 56 are positioned longitudinally in outletplenum 41 and are centrally connected by air tubes 57 and 58 throughlower shell 18 and lower casing 7 to an air pressure source such as airpump 59 on engine 2. A series of small openings 60 are provided alongair conduits 55 and 56 for injecting air into plenum 41.

Located in plenum 41 below air conduits 55 and 56 is first baffle 65,shown also in FIG. 3. Baffle 65 has a central opening 66 through whichthe exhaust gas/air mixture passes. Located below baffle 65 is secondbaffle 67, shown also in FIG. 4. Baffle 67 is provided with openings 68and 69 near its ends. Alternatively, baffle 67 can merely be madeshorter to provide an opening between its ends and the end wall of lowershell 18. Baffles 65 and 67 are flexibly suspended by brackets 70, 71,72 and 73 such that they can expand and contract at their own ratewithout placing a strain on inner housing 16.

In the embodiment shown, the converter contains both a catalyticreduction zone and a thermal oxidation zone. It is preferred that theengine be operated rich in order to insure a reducing gas in thecatalytic zone. This is done by adjusting the air/fuel ratio to achieveabout 1-4 percent CO in the exhaust gas. This generally requires anair/fuel ratio of about 12.5l4.5/1. The engine is started, and duringthe first minutes of operation air is injected into the engine exhaustports through passage 14 to provide an oxidizing gas (i.e., oxygen instoichiometric excess over hydrocarbon and carbon monoxide). This gaspasses through conduit 50 into inlet plenum 40 and then throughperforate wall 30 and screen 32 into the calalyst container. At thisstage the catalyst functions as an oxidation catalyst, which is a veryexothermic reaction and rapidly heats up the catalyst and inner housing16. After the first few minutes of operation, air injection into theexhaust ports is stopped and the exhaust gas immediately becomesreducing. The catalyst then functions to catalyze the chemical reductionof the nitrogen oxides in the exhaust.

Any of a large number of heat-resistant exhaust gas catalysts can beused. Preferred catalysts are those containing a Group V-B, Vl-B, VII-B,VIII or I-B metal or metal oxide on a suitable support such as alumina,silica-alumina, silica-magnesia-alumina, cordierite, mullite, and thelike. The catalyst may be an unsupported metal such as copper screen,copper wire, nickel turnings, copper-nickel alloy (Monel) turnings, andthe like. Examples of useful catalysts are copper oxide, copperoxide-vanadia, vanadia, copper oxide-chromia, nickel oxide, manganeseoxide, copper oxide-nickel oxide, copper-nickel-iron oxides, and thelike, on an alumina support. Useful catalysts are described in US. Pat.No. 3,545,917; 3,483,138; 3,552,913; 3,540,838; 3,524,721; 3,447,893;3,433,581; 3,374,183; 3,271,324; 3,226,340 and Fr. 2,109,662.

The treated exhaust gas leaves catalyst container 25 by passing throughscreen 33 and perforate outlet wall 31 and enters outlet plenum 41. Airis injected into the exhaust gas through air conduits 55 and 56 in anamount sufficient to render the exhaust gas oxidizing but not an amountwhich would cool the gas and prevent oxidation. As soon as the exhaustgas/air mixture forms. oxidation initiates spontaneously causing alowering in the hydrocarbon and carbon monoxide content of the gas. Theoxidizing gas mixture passes through central opening 66 in baffle 65 andimpinges against baffle 67. It then passes through openings 68 and 69 inbaffle 67 and, finally, leaves the inlet plenum through exhaust outlet14 and is conducted to the atmosphere through exhaust pipe 3.

The embodiment described includes both catalytic n reduction stage andathermal; oxidation stage. In other embodiments, either of these stagescan be omitted. ln other words, catalyst container 25 in FIGS. 1 and 2can be omitted to obtain a thermal (non-catalytic) reactor which hasimproved durability dueto its method of construction. Likewise, catalystcontainer 25 can be retained and air conduits 55 and 56 and baffles 65and 67 omitted to obtain a catalytic reactor of improved durability. Theresultant catalytic reactor can be used to reduce nitrogen oxides, as inthe present embodiment, or, by operating the engine leaner (above /1air/fuel ratio) and/or by continuously injecting air into the exhaustports, it can be used as a catalytic oxidation reactor. All of theseembodiments will have improved durability and faster heat-up compared toa conventional unit because of the manner of construction heretoforedescribed at which the following claims are directed.

We claim:

1. A thermal exhaust converter adapted to connect directly to theexhaust outlets of an internal combustion engine, said convertercomprising an elongated outer converter housing and an elongated innerconverter housing, said outer housing comprising an upper open-sidedcasing and a lower open-sided casing, the open sides of which join toform said outer housing, said inner housing comprising an upperopen-sided shell and a lower open-sided shell, the open sides of whichflexibly join to form said inner housing, longitudinal recesses insidesaid outer housing along the line of joinder of said upper casing tosaid lower casing, Longitudinal outwardly extending flanges along thelongitudinal edge of said upper shell and said lower shell. said flangesbeing slidably fit into said longitudinal recesses to flexibly suspendsaid inner housing inside said outer housing, exhaust inlet meansadapted to connect directly to the exhaust outlets of an internalcombustion engine and conduct exhaust gas into said inner housing,exhaust outlet means adapted to conduct treated exhaust gas from saidinner housing out through said outer housing and means for injecting airinto said exhaust gas such that said air mixes with said exhaust gas insaid inner housing thereby thermally oxidizing the combustibles in saidexhaust gas.

2. An exhaust converter of claim 1 having a baffle flexibly suspendedlongitudinally within said inner housing after' said means for injectingair, said baffle increasing mixing of said air and exhaust gas.

3. An exhaust converter of claim 1 wherein said exhaust inlet meanscomprises extensions in said outer housing adapted to connect rigidly tosaid exhaust outlets of said engine and a flexibly connected inlet tubewithin each of said extensions adapted to form a conduit from each ofsaid exhaust outlets of said engine into said inner housing.

4. An exhaust converter of claim 3 having a baffle flexibly suspendedlongitudinally within said inner housing after said means for injectingair, said baffle increasing mixing of said air and exhaust gas.

5. An exhaust converter adapted to connect directly to the exhaustoutlets of an internal combustion engine, said converter comprising anouter converter housing and an inner converter housing flexiblysuspended within said outer converter housing, said outer converterhousing comprising an upper open-sided casing and a lower open-sidedcasing, the open sides of which join to form said outer converterhousing, said inner *converter housing comprising an upper open-sidedshell and a lower open-sided shell, the open sides of which flexiblyjoin to form said inner converter housing, longitudinal recesses insidesaid outer converter housing along the line of joinder of said uppercasing to said lower casing, longitudinal outwardly extending flangesalong the longitudinal edges of said upper shell and said lower shell,said flanges being slidably fit into said longitudinal recesses toflexibly suspend said inner housing inside said outer housing, saidinner converter housing having a catalyst container therein partitioningsaid inner housing into an inlet plenum above said catalyst containerand an outlet plenum below said calalyst container, said upper casinghaving exhaust inlets adapted to connect directly to the exhaust outletsof said engine, inlet means adapted to deliver exhaust gas from saidexhaust inlets into said inlet plenum, outlet means to permit treatedexhaust gas to escape said outlet plenum, said catalyst container beingformed by an upper perforate inlet wall and a lower perforate outletwall joined by enclosing side walls, channel members attachedlongitudinally to said catalyst container, longitudinal catalystcontainer support members slidably fit between said flanges in saidrecesses such that a longitudinal edge of said support members extendsinwardly into said inner housing and slidably fits into said channelmembers on said catalyst container to flexibly suspend said catalystcontainer inside said inner housing.

6. An exhaust converter of claim 5 including flexibly connected inlettubes within said exhaust inlets of said outer converter housing adaptedto form conduits from said exhaust outlets of said engine into saidinlet plenum.

7. An exhaust converterof claim 6 having insulation between said innerconverter housing and said outer converter housing.

8. An exhaust converter of claim 5 further characterized by includingmeans for injecting air into said outlet plenum such that said outletplenum functions as a thermal oxidative reactor compartment 9. Anexhaust converter of claim 8 having upward opening channel members alongedges of the ends of said lower open-sided shell and extensions of theedges of the ends of said upper open-sided shell, said extensions beingslidably fit into said upward opening channel members to substantiallysealably connect the edges surrounding the open sides of said upper andlower shells in a flexible manner.

10. An exhaust converter of claim 9 having transverse channels at theends of said catalyst container and transverse angle members slidablyfit into said transverse channels and into said upward opening channelmembers to substantially seal said inlet plenum from said thermalreactor compartment except for the path through said perforate inlet andoutlet walls of said catalyst container.

11. An exhaust converter of claim 10 having a longitudinal first baffleflexibly suspended inside said thermal reactor compartment between saidcatalyst container and said outlet means, said air injection means beingprovided in the space between said first baffle and said catalystcontainer.

12. An exhaust converter of claim 11 having a second baffle flexiblysuspended between said first baffle and said outlet means.

13. An exhaust converter of claim 12 wherein said fist baffle has anopening proximate to its longitudinal center and said second baffle hasopenings proximate to both ends providing an elongated exhaust flowpath.

14. An exhaust converter of claim 8 including means for anchoring saidlongitudinal outwardly extending flange of said upper and loweropen-sided shells at a central location in said longitudinal recessessuch that said upper and lower open-sided shells expand and contractsubstantially equally in both directions inside said outer converterhousing.

15. An exhaust converter of claim 8 having a-longitudinal first baffleinside said thermal reactor compartmcnt between said catalyst containerand said outlet means, said air injection means being provided in thespace between said first baffle and said catalyst containcr.

16. An exhaust converter of claim 15 wherein said first baffle isflexibly suspended.

17. An exhaust converter of claim 16 having a second baffle flexiblysuspended between said first baffle and said outlet means.

18. An exhaust converter of claim 17 wherein said first baffle has anopening proximate to its longitudinal center and said second baffle hasopenings proximate to both ends providing an elongated exhaust gas flowpath.

1. A THERMAL EXHAUST CONVERTER ADAPTED TO CONNECT DIRECTLY TO THEEXHAUST OUTLETS OF AN INTERNAL COMBUSTION ENGINES, SAID CONVERTERCOMPRISING AN ELONAGATED OUTER CONVERTER HOUSING AND AN ELONGATED INNERCONVERTER HOUSING, SAID OUTER HOUSING COMPRISING AN UPPER OPEN-SIDEDCASING AND A LOWER OPENSIDED CASING, THE OPEN SIDES OF WHICH JOIN TOFORM SAID OUTER HOUSING, SAID INNER HOUSING COMPRISING AN UPPEROPEN-SIDED SHELL AND A LOWER OPEN-SIDED SHELL, THE OPEN SIDES OF WHICHFLEXIBLY JOIN TO FORM SAID INNER HOUSING, LONGITUDINAL RECESSES INSIDESAID OUTER HOUSING ALONG THE LINE OF JOINER OF SAID UPPER CASING TO SAIDLOWER CASING, LONGITUDINAL OUTWARDLY EXTENDING FLANGES ALONG THELONGITUDINAL EDGE OF SAID UPPER SHELL AND SAID LOWER SHELL, SAID FLANGESBEING SLIDABLY FIT INTO SAID LONGITUDINAL RECESSES TO FLEXIBLY SUSPENDSAID INNER HOUSING INSIDE SAID OUTER HOUSING, EXHAUST INLET MEANSADAPTED TO CONNECT DIRECTLY TO THE EXHAUST OUTLETS OF AN INTERNALCOMBUSTION ENGINE AND CONDUCT EXHAUST GAS INTO SAID INNER HOUSING,EXHAUST OUTLET MEANS ADAPTED TO CONDUCT TREATED HOUSING AND MEANS FORINNER HOUSING OUT THROUGH SAID OUTER HOUSING AND MEANS FOR INJECTING AIRINTO SAID EXHAUST GAS SUCH THAT AIR MIXES WITH SAID EXHAUST GAS IN SAIDINNER HOUSING THEREBY THERMALLY OXIDIZING THE COMBUSTIBLES IN SAIDEXHAUST GAS.
 2. An exhaust converter of claim 1 having a baffle flexiblysuspended longitudinally within said inner housing after said means forinjecting air, said baffle increasing mixing of said air and exhaustgas.
 3. An exhaust converter of claim 1 wherein said exhaust inlet meanscomprises extensions in said outer housing adapted to connect rigidly tosaid exhaust outlets of said engine and a flexibly connected inlet tubewithin each of said extensions adapted to form a conduit from each ofsaid exhaust outlets of said engine into said inner housing.
 4. Anexhaust converter of claim 3 having a baffle flexibly suspendedlongitudinally within said inner housing after said means for injectingair, said baffle increasing mixing of said air and exhaust gas.
 5. Anexhaust converter adapted to connect directly to the exhaust outlets ofan internal combustion engine, said converter comprising an outerconverter housing and an inner converter housing flexibly suspendedwithin said outer converter housing, said outer converter housingcomprising an upper open-sided casing and a lower open-sided casing, theopen sides of which join to form said outer converter housing, saidinner converter housing comprising an upper open-sided shell and a loweropen-sided shell, the open sides of which flexibly join to form saidinner converter housing, longitudinal recesses inside said outerconverter housing along the line of joinder of said upper casing to saidlower casing, longitudinal outwardly extending flanges along thelongitudinal edges of said upper shell and said lower shell, saidflanges being slidably fit into said longitudinal recesses to flexiblysuspend said inner housing inside said outer housing, said innerconverter housing having a catalyst container therein partitioning saidinner housing into an inlet plenum above said catalyst container and anoutlet plenum below said calalyst container, said upper casing havingexhaust inlets adapted to connect directly to the exhaust outlets ofsaid engine, inlet means adapted to deliver exhaust gas from saidexhaust inlets into said inlet plenum, outlet means to permit treatedexhaust gas to escape said outlet plenum, said catalyst container beingformed by an upper perforate inlet wall and a lower perforate outletwall joined by enclosing side walls, channel members attachedlongitudinally to said catalyst container, longitudinal catalystcontainer support members slidably fit between said flanges in saidrecesses such that a longitudinal edge of said suppOrt members extendsinwardly into said inner housing and slidably fits into said channelmembers on said catalyst container to flexibly suspend said catalystcontainer inside said inner housing.
 6. An exhaust converter of claim 5including flexibly connected inlet tubes within said exhaust inlets ofsaid outer converter housing adapted to form conduits from said exhaustoutlets of said engine into said inlet plenum.
 7. An exhaust converterof claim 6 having insulation between said inner converter housing andsaid outer converter housing.
 8. An exhaust converter of claim 5 furthercharacterized by including means for injecting air into said outletplenum such that said outlet plenum functions as a thermal oxidativereactor compartment
 9. An exhaust converter of claim 8 having upwardopening channel members along edges of the ends of said lower open-sidedshell and extensions of the edges of the ends of said upper open-sidedshell, said extensions being slidably fit into said upward openingchannel members to substantially sealably connect the edges surroundingthe open sides of said upper and lower shells in a flexible manner. 10.An exhaust converter of claim 9 having transverse channels at the endsof said catalyst container and transverse angle members slidably fitinto said transverse channels and into said upward opening channelmembers to substantially seal said inlet plenum from said thermalreactor compartment except for the path through said perforate inlet andoutlet walls of said catalyst container.
 11. An exhaust converter ofclaim 10 having a longitudinal first baffle flexibly suspended insidesaid thermal reactor compartment between said catalyst container andsaid outlet means, said air injection means being provided in the spacebetween said first baffle and said catalyst container.
 12. An exhaustconverter of claim 11 having a second baffle flexibly suspended betweensaid first baffle and said outlet means.
 13. An exhaust converter ofclaim 12 wherein said fist baffle has an opening proximate to itslongitudinal center and said second baffle has openings proximate toboth ends providing an elongated exhaust flow path.
 14. An exhaustconverter of claim 8 including means for anchoring said longitudinaloutwardly extending flange of said upper and lower open-sided shells ata central location in said longitudinal recesses such that said upperand lower open-sided shells expand and contract substantially equally inboth directions inside said outer converter housing.
 15. An exhaustconverter of claim 8 having a longitudinal first baffle inside saidthermal reactor compartment between said catalyst container and saidoutlet means, said air injection means being provided in the spacebetween said first baffle and said catalyst container.
 16. An exhaustconverter of claim 15 wherein said first baffle is flexibly suspended.17. An exhaust converter of claim 16 having a second baffle flexiblysuspended between said first baffle and said outlet means.
 18. Anexhaust converter of claim 17 wherein said first baffle has an openingproximate to its longitudinal center and said second baffle has openingsproximate to both ends providing an elongated exhaust gas flow path.